Mosseri emphasized that Facebook is merely talking to Apple and Microsoft so far. Nothing had been finalized.

“We’ve shown them what we’ve built and we’re just in an ongoing conversation,” Mosseri said in the interview.

Facebook Home is a replacement for your smartphone's home screen that gives Facebook center stage, rather than your apps. It basically turns your phone's main screen into something called "Cover Feed" that shows updates and photos from your friends. It also lets you interact on Facebook without launching an app. Home will also eventually allow Facebook to serve ads to mobile devices, too.

It's harder for Facebook to build a version of Home for the iPhone or for Windows Phone because those operating systems are closely guarded by their owners. Apple or Microsoft would have to consent. Google's Android, in contrast, is open source, making it easier for developers to do things like build an app that modifies something big like the home screen.

So even if Facebook is successful with these talks, the resulting app could be very different from the Android version of Home